This study provides a comprehensive review of earthship thermal performance in the Adelaide area of Australia

Conclusions:

“…for all exterior wall types, the heating and cooling load was less when heavy weight interior walls (mud brick) walls were employed rather than light weight (plaster board on stud). “The results… indicate that when a greenhouse (with solar controlled blinds) is” used, “there are energy savings for all wall types. Those that benefit the most are timber frame, rammed earth, and brick veneer… earthship has the least to gain from the greenhouse, with an energy saving of only 505kWh” annually.

Reviewers note: To put this in perspective, the US Energy Information Administration puts the cost of a kWh of electricity at $0.13 as of August 2014. That equates to a savings of $65.65 per year over traditional power. That savings is easily eaten up in the $40+k cost of the greenhouse, however.

“Similar performance was achieved by the insulated and bermed concrete block wall indicating that this wall construction method offers an alternative to the tire wall.” “…without the berm these”(two systems: earthship and block) “perform similarly to strawbale and insulated rammed earth. When the design incorporates a greenhouse” (brick veneer also has a…) ”good result indicating that traditional materials with passive solar design principles could lead to significant energy savings."

This research points to several
resolutions we must find if the earthship ideals are to be realized. The
chapter that addresses the issue in Part 2 of this book is listed after the
issue if we address it: